I face more and more strange code-share situations with AFKL and I don't understand the logic behind. It is very frequent, for instance, if you book a ticket to the US involving a domestic connection on DL, to see AF flights CDG-USA hub only proposed under KL code and not under AF code. To make it clearer, let's say you book CDG-BNA via JFK with CDG-JFK is AF-operated and JFK-BNA is DL-operated, the whole itinerary is proposed under KL code and not AF. It's not that it matters a lot in practice, but I don't see the reason behind for not having an AF flight sold under AF code, knowing that the code-share agreement with DL is a free flow one.

And I just faced another weird situation. I wanted to book a MAD-BOS round trip, under AF (or KL) code for UXP earning. There is a nonstop DL flight but AF and KL systems (desktop sites and apps) were only proposing this flight under the native DL code. I was thinking that all DL flights Europe-US were also available as JV partner code-shares but it was nowhere to be found. Even if using the Spanish POS, the flight was not proposed under AFKL code.
I looked on Expedia and it was indeed bookable either with DL code or AF code (AF9110 / AF9111). I prefer buying direct with the airline so I called the Ulti TA but they were not seeing it under AF code. I ended up buying the ticket on Expedia. Go figure...

Any comment welcome.